Why You Can’t Make a Good Decision at 5:00 pm: Decision Fatigue

We live in the most prosperous society on Earth at this moment. You can walk into any Gap or Target store and choose from more than 2 dozen different types of jeans (and in some cases, more than 3 dozen).

All of that choice comes at a price, however. It’s called “decision fatigue” and its full impact is only starting to be fully understood by psychologists and researchers.

Our brains can suffer from “mental fatigue,” just as our bodies can become physically fatigued after a long workout. What is so surprising about this phenomenon is just how little people appreciate the importance of mental fatigue and its resulting decision fatigue — even when making decisions that can be life-changing.

John Tierney in The New York Times has the lengthy story (5,350 words, so settle in with your favorite beverage).

Decision fatigue helps explain why ordinarily sensible people get angry at colleagues and families, splurge on clothes, buy junk food at the supermarket and can’t resist the dealer’s offer to rustproof their new car. No matter how rational and high-minded you try to be, you can’t make decision after decision without paying a biological price. It’s different from ordinary physical fatigue — you’re not consciously aware of being tired — but you’re low on mental energy. The more choices you make throughout the day, the harder each one becomes for your brain, and eventually it looks for shortcuts, usually in either of two very different ways.

One shortcut is to become reckless: to act impulsively instead of expending the energy to first think through the consequences. (Sure, tweet that photo! What could go wrong?) The other shortcut is the ultimate energy saver: do nothing. Instead of agonizing over decisions, avoid any choice. Ducking a decision often creates bigger problems in the long run, but for the moment, it eases the mental strain. You start to resist any change, any potentially risky move — like releasing a prisoner who might commit a crime. So the fatigued judge on a parole board takes the easy way out, and the prisoner keeps doing time.

One solution to the negative effects of decision fatigue? Glucose replenishment in the brain.

[Researcher] Heatherton’s results did much more than provide additional confirmation that glucose is a vital part of willpower; they helped solve the puzzle over how glucose could work without global changes in the brain’s total energy use. Apparently ego depletion causes activity to rise in some parts of the brain and to decline in others.

Your brain does not stop working when glucose is low. It stops doing some things and starts doing others. It responds more strongly to immediate rewards and pays less attention to long-term prospects.

Tierney goes on to explain why this makes dieting so difficult. Dieters start out with good intentions and can readily make the tough choices to eat healthy. But by the end of the day, their brains are running out of the energy needed to keep fueling those good decisions. So they start hedging their choices, and run out of willpower to resist the sweets or other temptations.

Sugar is an obvious way to get glucose, hence the reason why so many dieters crave it. But spikes of glucose that come from sweets are much worse for both our brains and our bodies, because they don’t help the brain with long-term glucose levels. The brain quickly consumers the temporary glucose spike, then settles back into its glucose deficit an hour later.

Fixes for how people deal with important decisions — like a parole board — are relatively easy. Restrict their time while on the job, give the judges more breaks. But helping decision fatigue in our everyday lives is apparently much more challenging.

The results [of a study examining how often people try to resist a desire throughout the day] suggested that people spend between three and four hours a day resisting desire. Put another way, if you tapped four or five people at any random moment of the day, one of them would be using willpower to resist a desire. The most commonly resisted desires in the phone study were the urges to eat and sleep, followed by the urge for leisure, like taking a break from work by doing a puzzle or playing a game instead of writing a memo. Sexual urges were next on the list of most-resisted desires, a little ahead of urges for other kinds of interactions, like checking Facebook.

To ward off temptation, people reported using various strategies. The most popular was to look for a distraction or to undertake a new activity, although sometimes they tried suppressing it directly or simply toughing their way through it. Their success was decidedly mixed. They were pretty good at avoiding sleep, sex and the urge to spend money, but not so good at resisting the lure of television or the Web or the general temptation to relax instead of work.

The worse part about decision fatigue is most of us don’t realize how often it’s happening, or its impact on our decision-making process throughout a typical day:

The cumulative effect of these temptations and decisions isn’t intuitively obvious. Virtually no one has a gut-level sense of just how tiring it is to decide. Big decisions, small decisions, they all add up. Choosing what to have for breakfast, where to go on vacation, whom to hire, how much to spend — these all deplete willpower, and there’s no telltale symptom of when that willpower is low.

The upshot? Don’t make important decisions late in the day or in the evening. Make your best and most important decisions before lunch. Whether it’s buying a car, a new house, deciding to switch jobs, or end a relationship. Make the important decisions in your life when you’re well-rested and the glucose levels in your brain are at their highest, typically first thing in the day. And eat a good breakfast to get the fuel your brain needs.

Related Articles

About John M. Grohol, Psy.D.

Dr. John Grohol is the founder & CEO of Psych Central. He is an author, researcher and expert in mental health online, and has been writing about online behavior, mental health and psychology issues -- as well as the intersection of technology and human behavior -- since 1992. Dr. Grohol sits on the editorial board of the journal Computers in Human Behavior and is a founding board member and treasurer of the Society for Participatory Medicine.